1. Field of the Invention
The present invention relates generally to artificial body members, and more importantly, pertains to a pivoting disc heart valve.
2. Description of the Prior Art
The replacement of damaged or diseased natural heart valves with mechanical heart valves has become medically quite common. Of the various mechanical heart valve designs which have been proposed, pivoting disc valves of the type disclosed, for example, in U.S. Pat. Nos. 3,825,957 and 4,021,863, have the significant feature of providing minimal interference to blood flow through the heart valve. The valves of the two above-mentioned patents each employ a pivoting disc having a center hole and a guide strut which extends through the center hole guiding the disc between its open and closed positions. The valves include a generally annular valve body having various inwardly directed projections arising from its inner surface where the projections act as pivot surfaces urging the disc to pivot between open and closed positions in response to cyclic blood pressure differentials across the valve. The manufacture of the valves such as those described in the above-mentioned patents is a meticulous process which involves machining and polishing the valve body and associated disc-supporting structure to exacting tolerances.
Heart valves should disturb blood flow as little as possible. The orifice of the heart valve should be as free as possible of internal projections disturbing the blood flow. It is particularly important from the standpoint of blood flow dynamics that the heart valve be as free as possible of obstructions immediately upstream from the orifice of the heart valve. On the other hand, in order to avoid interference with the heart valve operation from encroaching heart tissue downstream of the heart valve, the heart valve should further be as free as possible of physical structure extending downstream from the heart valve. Finally, the heart valve must be structurally strong, and be physically capable of reliable operation in opening and closing through millions of cycles.
The pivoting disc heart valve of the present invention incorporates a pivot integrally onto a central guide strut. The guide strut provides for positive retention of a radiopaque occluder, and simplifies manufacture.